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Biomedical subjects

F R Miller

Publications and source records attributed to F R Miller.

At least 37 records · Page 2Linked to original sources
PubMed1998

Use of tumor lines with selectable markers in assessing the effect on experimental metastases of combination chemotherapy with alkylating agents.

High-dose chemotherapy with a 3-day regimen of cyclophosphamide, cisplatin, and carmustine was used to treat mice bearing experimental lung metastases of mammary tumor cell lines with selectable markers (lines 66cl4 and 4TO7). Cloning of lung cells at various times after treatment revealed a rapid 3 to 4 log loss of clonogenic tumor cells, down to undetectable levels. However, after several weeks, clonogenic tumor cells reappeared in the lungs; few cures were obtained even when mice had a relatively low tumor burden when treated with chemotherapy. Splenocyte numbers and response to Concanavalin A indicated a transient immunosuppression. In one experiment, mice were treated with a second round of chemotherapy 3 weeks after the first. The number of clonogenic cells per lung again dropped, but regrowth of cells was rapid, and no cures were obtained. Inoculation of tumor-bearing mice s.c. after chemotherapy with lethally irradiated cells of the highly immunogenic tumor cell line 4TO7-IL-2 had little effect on the rate of reappearance of line 4TO7 in lungs, but subsequent growth of tumor cells in lungs was slowed. This model system can be used to test the efficacy of additional immunotherapy and chemotherapy regimens on minimal residual metastatic disease after high-dose chemotherapy, when remaining metastatic cells are apparently dormant.

Animals↗
PubMed1998

Altered expression of c-erbB-2, DF3, b72.3, p53 and Ki-67 with progression and differentiation to two distinct histologic types of invasive carcinoma in the MCF10AT human xenograft model of proliferative breast disease.

Human breast epithelial MCF10AT cells form simple ducts in nude/beige mice which eventually become hyperplastic and sporadically progress to carcinomas. Altered immunohistochemical detection of c-erbB-2, DF3, B72.3, p53 and Ki-67 was observed with progression and differentiation to two distinct histologic types of invasive carcinoma. c-erbB-2 and DF3 were detected in 50% and 18% of lesions at the stage of atypical hyperplasia and expression increased to 78% and 54% in invasive adenocarcinomas. In contrast, a group of six unusual undifferentiated tumors with squamoid features did not express c-erbB-2 or DF3, but both B72.3 (4/6) and p53 (6/6) were detected.

Adenocarcinoma↗
PubMed1998

Transcriptional activation of functional endogenous estrogen receptor gene expression in MCF10AT cells: a model for early breast cancer.

Utilizing the MCF10AT xenograft model for progression of human proliferative breast disease, we detected expression of the endogenous estrogen receptor (ER) gene only in MCF10AneoT and cells of the MCF10AT system, all of which stably express a transfected mutated T24 Ha-ras gene. ER transcripts were undetectable in the parental MCF10A cells and in MCF10A cells transfected with normal c-Ha-ras or vector. ER transcripts expressed in MCF10AT cells contain a normal full-length ER coding region and direct synthesis of a normally sized ER protein. The protein is functional based on its ability to mediate estradiol (E2)-induced increases of transcription from both endogenous and exogenous E2-regulated genes. Transcriptional activation of the endogenous ER gene does not appear to be related to a change in methylation status of the gene since a diagnostic CpG site in exon 1 that is methylated in ER-negative breast tumors and completely unmethylated in ER-positive breast tumors is hypomethylated to the same extent in ER-negative MCF10A cells and ER-positive MCF10AT cells. E2 increased both the number and size of soft-agar colonies formed by MCF10AT3c cells, a line from a third generation MCF10AT xenograft lesion. This suggests that xenograft passage has selected for growth regulatory pathways that are E2-responsive and that identification of these pathways and their role in progression will aid in determining how E2 acts to increase risk of breast cancer.

Animals↗
PubMed1997

The sorghum photoperiod sensitivity gene, Ma3, encodes a phytochrome B.

The Ma3 gene is one of six genes that regulate the photoperiodic sensitivity of flowering in sorghum (Sorghum bicolor [L.] Moench). The ma3R mutation of this gene causes a phenotype that is similar to plants that are known to lack phytochrome B, and ma3 sorghum lacks a 123-KD phytochrome that predominates in light-grown plants and that is present in non-ma3 plants. A population segregating for Ma3 and ma3 was created and used to identify two randomly amplified polymorphic DNA markers linked to Ma3. These two markers were cloned and mapped in a recombinant inbred population as restriction fragment length polymorphisms. cDNA clones of PHYA and PHYC were cloned and sequenced from a cDNA library prepared from green sorghum leaves. Using a genome-walking technique, a 7941-bp partial sequence of PHYB, was determined from genomic DNA from ma3 sorghum. PHYA, PHYB, and PHYC all mapped to the same linkage group. The Ma3-linked markers mapped with PHYB more than 121 centimorgans from PHYA and PHYC. A frameshift mutation resulting in a premature stop codon was found in the PHYB sequence from ma3 sorghum. Therefore, we conclude that the Ma3 locus in sorghum is a PHYB gene that encodes a 123-kD phytochrome.

Amino Acid Sequence↗
PubMed1996

Models of progression spanning preneoplasia and metastasis: the human MCF10AneoT.TGn series and a panel of mouse mammary tumor subpopulations.

The two models described offer an opportunity to determine relevant genetic alterations during progression from preneoplasia to metastatic disease while avoiding genetic noise among individuals (patients and mice) and independent cancers. The human preneoplastic MCF10AneoT.TGn model allows the identification of altered genes as progression occurs sporadically and affords a method of directly testing the gene affect by introduction into non-expressing variants. The model also will allow testing suspected oncogenes and suppressor genes identified in other cancers. However, its value in the latter studies may be limited because genes may not alter MCF10AneoT phenotypes due to other unidentifiable differences between the MCF10 model and the cancer in which the gene was identified. The mouse model allows similar cause and effect studies to determine at which specific steps metastasis genes might be important. The model also provides an opportunity to determine which host response elements are important deterrents at each step in metastasis and in different organ sites. Together, these models have the potential to elucidate a genetic sequence of progression in breast comparable with that being constructed for colon carcinoma [16].

Animals↗
PubMed1996

MCF10AT: a model for the evolution of cancer from proliferative breast disease.

A human cell line (MCF10A) originated from spontaneous immortalization of breast epithelial cells obtained from a patient with fibrocystic disease. MCF10A cells do not survive in vivo in immunodeficient mice. However, T24 c-Ha-ras oncogene-transfected MCF10A cells (MCF10AT) form small nodules in nude/beige mice that persist for at least 1 year and sporadically progress to carcinomas. By reestablishing cells in tissue culture from one of the carcinomas, a cell line designated MCF10AT1 was derived that forms simple ducts when transplanted in Matrigel into immunodeficient mice. With time in vivo, the epithelium becomes proliferative and a cribriform pattern develops within the xenografts. A significant number progress to lesions resembling atypical hyperplasia and carcinoma in situ in women, and approximately 25% progress to invasive carcinomas with various types of differentiation including glandular, squamous, and undifferentiated. Cells have been established in culture from lesions representing successive transplant generations. With each generation, cells are somewhat more likely to progress to high risk lesions resembling human proliferative breast disease. Although the incidence of invasive carcinoma remained fairly constant at 20 to 25%, the frequency of nodules showing proliferative breast disease rose from 23% in the first transplant generation to 56% in the fourth transplant generation.

Animals↗
PubMed1995

Tumor suppression by p21WAF1.

The p21WAF1 gene encodes a cyclin-dependent kinase inhibitor and mediates tumor suppressor gene p53-induced cell cycle arrest. To directly test whether p21WAF1 can act as a tumor suppressor, we have expressed the p21WAF1 cDNA in several human tumor cell lines using a tetracycline-inducible system. Overexpression of p21WAF1 suppresses proliferation and soft agar growth of tumor cells in vitro, as well as tumorigenicity in vivo. Our data provide direct evidence for the tumor-suppressive activity of p21WAF1.

Animals↗
PubMed1995

Long-term flap tracheostomy in a pediatric animal model.

OBJECTIVE: To investigate the short- and long-term complications of pediatric tracheostomy, emphasizing posttracheostomy tracheal stenosis in an animal model. DESIGN: Twenty-five New Zealand white rabbits were randomly assigned to three groups: flap tracheostomy, traditional vertical tracheostomy, and control. Interactive image analysis was used to compare the tracheal cross-section area and circumference between groups 16 weeks after surgery. The incidence of peristomal infections and accidental decannulations was also compared. RESULTS: The vertical tracheostomy group had a smaller circumference (P = .01) and smaller cross-sectional area (P = .006) than the control or flap tracheostomy groups. A 30% decrease in tracheal cross-sectional area occurred in the vertical tracheostomy group. The flap tracheostomy group had fewer problems with accidental decannulation and peristomal infection compared with the vertical tracheostomy group. CONCLUSIONS: We found no significant risk of tracheal stenosis or adverse effects on tracheal growth for the flap tracheostomy in a developing animal model. This tracheostomy technique may be useful in the management of pediatric patients who require long-term bypass of the upper airway.

Animals↗
PubMed1995

Electronic integration of glottic closure and circopharyngeal relaxation for the control of aspiration: a canine study.

Aspiration can result from muscular weakness or paralysis of laryngopharyngeal muscles after lower motor neuron disorders (e.g., stroke) or unchecked gastroesophageal reflux. We submit that rehabilitation of the finely tuned swallowing mechanism should provide at least restoration of the normal dynamic relationships between glottic closure and cricopharyngeal relaxation. In three dogs under general endotracheal anesthesia, the recurrent laryngeal nerves and the pharyngeal musculature were exposed through a midline cervical incision. A tracheotomy was performed to allow unhindered laryngoscopic exposure of the vocal cords. A no. 9 endotracheal tube passed through the upper esophageal sphincter was used as a pressure transducer by saline inflation of its cuff and linked to an oscilloscope. The cricopharyngeus was placed under baseline tension with pulse trains administered by an intramuscular needle with a circuit previously used for agonist/antagonist coupling of reinnervated facial musculature. A second output channel was linked to the contralateral recurrent laryngeal nerve by a bipolar electrode. As the pulse width of the current to the recurrent laryngeal nerve increased, that to the cricopharyngeus was reciprocally decreased, producing snug glottic closure and synchronous cricopharyngeal relaxation. Results were documented on videotape. These findings were highly reproducible. We believe that the novel approach proposed in the current model offers an attractive solution to long-term aspiration problems resulting from an imbalance between vocal cord and cricopharyngeal activities.

Animals↗
PubMed1995

Vocal fold medialization using autologous cartilage in a canine model: a preliminary study.

Unilateral vocal fold paralysis can alter phonation. Medialization of the vocal fold using cartilage augmentation dates to the early 1950s. Improved phonation after cartilage chordal augmentation has been reported, but no study has as yet documented cartilage viability or size in this setting over time. The authors of this study evaluated thyroid alar cartilage as a medializing material in three mongrel dogs. Grafts were inserted lateral to the inner thyroid perichondrium at the vocal fold level via a window in the thyroid cartilage. Changes in weight, size, and volume were assessed 6 months after implantation. The average graft weight declined by 15%, and the average square area declined by 3%. Importantly, the average volume maintained was 87%. The grafts remained rigidly fixed to the thyroid cartilage in their placement positions. Histologic examination documented minimal resorption. The data suggest that thyroid alar cartilage is a viable filler in type I thyroplasty procedures.

Animals↗
PubMed1994

Cricoarytenoid arthritis and ankylosing spondylitis.

A variety of systemic diseases may manifest with laryngeal symptoms. Cricoarytenoid arthritis with or without limitation of vocal fold motion is an example. It has been described in up to 25% of rheumatoid patients. Ankylosing spondylitis is classified among the seronegative spondylarthritides. Besides its systemic features, rare reports of cricoarytenoid involvement have been published. Six previous cases reported have been characterized by a long history of ankylosing spondylitis before the cricoarytenoid joint involvement occurred. We describe only the seventh case of cricoarytenoid arthritis secondary to ankylosing spondylitis and the first patient (to our knowledge) to present with bilateral vocal fold fixation as the initial presenting symptom.

Adult↗
PubMed1994

Artificial reflex arc: a potential solution for chronic aspiration. III: Stimulation of implanted cervical skin as a functional graft triggering glottic closure in the canine.

Stroke often impairs the ability of the vocal cords to close during deglutition, resulting in aspiration. The current study is a further advance on the application of the concept of an artificial reflex arc during swallowing. The second and third cervical branches were bilaterally isolated in four dogs and baseline sensory nerve traffic was detected via tripolar perineural electrodes. Cervical skin pressure-induced suprathreshold signals were used to trigger vocal cord contraction via bipolar electrodes passed around the recurrent laryngeal nerves. Skin subtended by the cervical nerves was implanted over the lateral aspect of the pyriform sinuses for 1 week. After reexploration, glottic closure was verified on videotape as surges in sensory nerve traffic were induced by mechanical stimulation of the pharynx. The possibility of artifactual stimulation was ruled out by lack of electrode motion during pharyngeal stimulation, spontaneous firing in the sensory nerve during light anesthesia, and sensory frequency differing from ambient 60-Hz noise. This article introduces the concept of autogenous functional graft as a basis for afferent information in electronic systems for dynamic rehabilitation of swallowing disorders.

Animals↗
PubMed1993

Xenograft model of progressive human proliferative breast disease.

BACKGROUND: Progression of proliferative breast disease has been associated with increased risk for development of invasive carcinoma. Cell lines have been developed to facilitate the study of this process. Human cell line MCF10A originated from spontaneous immortalization of breast epithelial cells obtained from a patient with fibrocystic disease, and cell lines MCF10AneoN and MCF10AneoT were created by stable transfection of these cells with the neomycin-resistance gene and either the HRAS gene or the mutated T-24 HRAS gene, respectively. PURPOSE: Our goal was to develop an experimental model of progressive human proliferative breast disease. METHODS: MCF10A, MCF10AneoN, and MCF10AneoT cells were injected subcutaneously into the dorsal flank of male nude/beige (C57/BALB/c nu/nu bg/bg) mice (12 mice for each cell type). These mice were examined periodically for formation and persistence or growth of palpable nodules. One mouse per group was killed 1 week after cell injection; thereafter, mice were observed as long as possible. Cells were recovered from palpable lesions by enzymatic dissociation of the excised lesions. Cells re-established in tissue culture from a week-14 tumor (MCF10AneoT.TG1) were injected into 12 male nude/beige mice. Southern blot hybridization analysis of the HRAS gene locus and cytogenetic analyses were performed. RESULTS: Transplanted MCF10A and MCF10AneoN cells formed transient, small palpable nodules that regressed and disappeared during the 4th and 5th weeks. In 10 of the 12 mice, T-24 HRAS gene-transfected MCF10A cells (MCF10AneoT) formed small, flat nodules that persisted for at least 1 year. Three of these xenografts became carcinomas. One (removed 7 weeks after transplantation) was an undifferentiated carcinoma composed of polygonal cells with large, vesicular nuclei and numerous mitoses. The second (removed after 14 weeks) was an invasive squamous cell carcinoma. The third (removed after 56 weeks) was a moderately differentiated adenocarcinoma. Initially, xenografts of MCF10AneoT.TG1 cells showed intraductal proliferative changes; after 23 weeks, the lesions showed histologic features resembling those seen in atypical hyperplasia of the human breast, and later lesions showed characteristics of carcinoma in situ. The MCF10 lineage of cells of three MCF10AneoT.TG1 xenografts was confirmed by DNA fingerprinting and karyotype analysis. CONCLUSIONS: MCF10AneoT and MCF10AneoT.TG1 comprise a transplantable xenograft model that produces a broad spectrum of human proliferative breast disease. IMPLICATIONS: The reproducible establishment of representative stages in early breast cancer progression from the MCF10 model offers a new opportunity to analyze critical events of carcinogenesis and progression in breast cancer.

Adult↗
PubMed1993

Induction of antitumor immunity by interleukin-2 gene-transduced mouse mammary tumor cells versus transduced mammary stromal fibroblasts.

BACKGROUND: Tumor cell-targeted cytokine gene transfer has been used to generate tumor cell vaccines, but this approach is limited by the need to establish and implant live tumor cells. PURPOSE: The purpose of this study was to determine if stromal fibroblasts could be used as an alternative vehicle for delivery of the cytokine interleukin-2 (IL-2) into the tumor microenvironment. We attempted to establish the feasibility of (a) genetic immunotherapy in a mammary tumor system and (b) engineering stromal fibroblasts as well as tumor cells. We compared the effects of tumor cell-mediated and stromal fibroblast-mediated local IL-2 expression on the generation of antitumor immune responses. METHODS: Retroviral vectors containing a human IL-2 gene were used to transduce a mouse mammary tumor line, 4TO7, and an immortalized but nontumorigenic fibroblast line established from syngeneic mammary fatpads. Expression of the IL-2 gene in transduced cells was determined by measuring IL-2 secretion, by RNA-polymerase chain reaction, and by immunochemistry. Groups of 5-12 BALB/c mice were injected with either 4TO7 cells or various doses of IL-2-secreting 4TO7 cells (4TO7-IL-2); tumor growth was monitored. To test whether local IL-2 expression by transduced cells could influence the growth of unmodified tumor cells, we determined tumor development in groups of mice treated with 4TO7 cells co-injected with either 4TO7-IL-2 cells or IL-2-secreting fibroblasts. RESULTS: 4TO7-IL-2 cells induced active immunity able to reject the immunizing tumor and to resist challenge with parental 4TO7 cells on the contralateral side. Mice pretreated with 4TO7-IL-2 were significantly protected compared with untreated control animals or mice pretreated with irradiated 4TO7 cells. The immunity induced by 4TO7-IL-2 cells did not protect against challenge with another subline, 4T1, which was derived from the same spontaneously arising mammary tumor as 4TO7. Co-injection of 4TO7 cells with 4TO7-IL-2 cells reduced tumorigenicity, whereas co-injection of 4TO7 cells with IL-2 secreting fibroblasts did not. CONCLUSION: Our results suggest that induction of anti-tumor immune response by local IL-2 production is most effective when the helper cytokine is secreted by the tumor cell. IMPLICATION: Our studies caution against the use of IL-2 gene-transduced syngeneic stromal cells as an alternative strategy of gene therapy for cancer. However, they may allow study of the mechanisms of tumor antigen recognition and the possible involvement of co-stimulatory signals for effective tumor vaccination by gene-modified cells.

Animals↗